As the primary cell responsible for deciding the early innate immune response to inhaled pathogens and particulates, the lung macrophage is required to make important judgment calls about the risks associated with inhaled materials. It is for this reason that we have been long fascinated by the delicate control lung macrophages have over IL-12. This IL- 12 control is important in lung inflammation and in response to infections since IL-12 represents one of the key determinants of lung inflammation in disorders as diverse as asthma, ARDS, pneumonia and pulmonary fibrosis. Having worked to understand macrophage regulation of IL-12 for over 2 decades, we are poised to greatly expand the knowledge of this regulation. IL-12 regulation is now at the center of a revolution of understanding about innate host mechanisms that make this central lung regulatory event poised for new discovery. We have previously noted that although normal lung macrophages contain abundant amounts of caspase-1 and generate IL-12 precursor, they are limited in their ability to activate the caspase-1 centered inflammasome. This control is likely to represent a central regulatory event that is modified in lung inflammatory diseases. This proposal will take advantage of our recent creation of a novel, high throughput system that we believe will allow us to screen human lung macrophages and human blood monocytes for key molecules that participate in the regulation of caspase-1. Specific aims are proposed to 1) optimize the conditions cell-free inflammasome system and 2) screen monocytes and macrophages for modulators of the inflammasome. We believe that this new inflammasome model will allow us to make rapid progress in the understanding of these events which we believe are central to most inflammatory lung disorders including asthma, ARDS, and pulmonary fibrosis. PUBLIC HEALTH RELEVANCE: Most inflammatory disorders (e.g. sepsis, acute lung injury, asthma, lung fibrosis and hardening of the arteries) are, at least in part, induced by overly active caspase-1, an enzyme that is central to releasing inflammatory hormones. In this context, the discovery of a complex of intracellular proteins that control this activation event provides an opportunity for discovery. This project would utilize a novel, high throughput system that we have recently devised to enhance discovery of caspase-1 regulatory components and the promise of finding new treatment approaches to these inflammatory diseases.